A STUDY OF REFRACTORY METERIALS FOR SEAL AND BEARING APPLICATIONS IN AIRCRAFT ACCESSORY UNITS AND ROCKET MOTORS

摘要

A number of ceramic, cermet, and high-temperature alloy materials have been evaluated for corrosion resistance and for friction and wear be¬havior in an oxidizing atmosphere from 1000 to 1800 F. Rubbing-wear ex-periments were conducted at 200 feet per second sliding speed with about 20-psi load pressure usually applied to the contact surfaces. Several ma-terial combinations involving an alumina-chromium-molybdenum cermet, silicon carbide, alumina, and perhaps a titanium carbide-nickel-molybdenum cermet may be satisfactory for short-life rubbing-seal applications under these conditions. The applications of these materials are limited since they wear rapidly and exhibit erratic frictional behavior. Superficial surface cracking was observed on the wear surfaces of all specimens containing brittle ceramic phases except possibly silicon carbide. A wear-failure mechanism for refractory materials under sliding contact is postulated, and some correlation of the experimental results with conventional thermal-stress-resistance parameters is obtained.